Auxiliary Ground Research Articles

Comparison of Auxiliary Power Unit (APU) and Ground Power Unit (GPU) with Life Cycle Analysis in Ground Operations: A Case Study for Domestic Flight in Turkey

In this study, the Auxiliary Power Unit (APU) and the Ground Power Unit (GPU) that are required meet the energy demand in ground operations of aircraft were compared in terms of their damages –human health (disability adjusted life years- DALYs), ecosystem quality (PDF.m2.yr) and resources (MJ Surplus). These damages were calculated with gate-to-gate method of Life Cycle Assessment (LCA). This assessment was held on three main stages; capital investment, operation and maintenance. SimaPro 7.2.4 was used for this calculation. Human Health Damages (HHDs) of APU were found to be (0.0557 -disability adjusted life years- DALYs) 20.34 days/year while HHDs of GPU were calculated as (0.0411 -disability adjusted life years-DALYs) 15 days/year. While Ecosystem Quality Damages (EQDs) of APU were calculated as 103366.37 PDF.m2.yr, EQDs of GPU were found to be 82651.23 PDF.m2.yr. In other words, although the use of APU gives rise to loss of 0.1 species –1 year, 1 square kilometer area, the use of GPU gives rise to loss of 0.083 species. With regards to Resources Damages (RDs), 62125 MJ surplus energy needed for future extractions of minerals and fossil fuel considering APU, one the other hand 36002 MJ surplus energy needed for future considering GPU. As a result, the use of APU effects on human health, ecosystem quality and resources was determined greater than the use of GPU for 30 minute. The use of GPU has less impact on human health, ecosystem quality and resources in ground operations.

Robust Scheme for Entangling Two Distant Atoms

A robust scheme is presented for realizing entangled states for two atoms trapped in separate cavities connected by an optical fiber. The first atom is initially in a superposition of the excited state and an auxiliary ground state not coupled to the first cavity, while the second one is initially in the ground state coupled to the second cavity. The scheme involves two atom-cavity-fiber interactions accompanied by the monitoring of the cavity decay and atomic spontaneous emission. The two atoms evolve to an entangled state through exchanging an excitation after the first interaction. The states with the excitation failing to be transferred are eliminated when a photon is detected during the second interaction. Therefore, the scheme is insensitive to the decoherence effect and detection inefficiency.

Air quality and public health impacts of UK airports. Part II: Impacts and policy assessment

The potential adverse human health impacts of emissions from UK airports have become a significant issue of public concern. We produce an inventory of UK airport emissions – including emissions from aircraft landing and takeoff operations, aircraft auxiliary power units (APUs) and ground support equipment (GSE) – with quantified uncertainty. Emissions due to more than 95% of UK passenger enplanements are accounted for. We apply a multi-scale air quality modelling approach to assess the air quality impacts of UK airports. Using a concentration-response function we estimate that 110 (90% CI: 72–160) early deaths occur in the UK each year (based on 2005 data) due to UK airport emissions. We estimate that up to 65% of the health impacts of UK airports could be mitigated by desulphurising jet fuel, electrifying GSE, avoiding use of APUs and use of single engine taxiing. Two plans for the expansion of UK airport capacity are examined – expansion of London Heathrow and new hub airport in the Thames Estuary. Even if capacity is constrained, we find that the health impacts of UK airports still increases by 170% in 2030 due to an increasing and aging population, increasing emissions, and a changing atmosphere. We estimate that if Heathrow were to be expanded as per previous UK Government plans, UK-wide health impacts in 2030 would increase by 4% relative to the 2030 constrained case, but this increase could become a 48% reduction if emissions mitigation measures were employed. We calculate that 24% of UK-wide aviation-attributable early deaths could be avoided in 2030 if Heathrow were replaced by a new airport in Thames Estuary because the location is downwind of London, where this reduction occurs notwithstanding the increase in aircraft emissions. A Thames hub airport would (isolated from knock-on effects at other airports) cause 60–70% fewer early deaths than an expanded Heathrow, or 55–63% fewer early deaths than an unexpanded Heathrow. Finally, replacing Heathrow by a Thames Estuary airport combined with emissions mitigation measures would reduce UK-wide aviation-attributable early deaths by 56% in 2030 while increasing aircraft movements, which would represent aviation causing about the same level of adverse health impacts as today in absolute terms. We note that because aviation emissions are included in the EU Emissions Trading Scheme, all options are CO2-neutral in terms of direct emissions (but not climate-neutral).

Suspended Particulate Matter Concentrations Retrieved from Self-Calibrated Multispectral Satellite Imagery

Suspended Particulate Matter Concentrations Retrieved from Self-Calibrated Multispectral Satellite ImageryInland waters are known to be laden with high levels of suspended particulate matter (SPM). Remotely sensed data have been shown to provide a true synoptic view of SPM over vast areas. However, as to date, there is no universal technique that would be capable of retrieving SPM concentrations without a complete reliance on time-consuming and costly ground measurements ora prioriknowledge of inherent optical properties of water-borne constituents. The goal of this paper is to present a novel approach making use of the synergy found between the reflectance in the visual domain (~ 400-700 nm) with the near-infrared portion of the spectrum (~ 700-900 nm). The paper begins with a brief discourse of how the shape and spectral dependence of reflectance is determined by high concentrations of SPM. A modeled example is presented to mimic real-world conditions in fluvial systems, with specific absorption and scattering coefficients of the virtual optically active constituents taken from the literature. Using an optical model, we show that in the visual spectral domain (~ 400-700 nm) the water-leaving radiance responds to increasing SPM (0-100 g m-3) in a non-linear manner. Contrarily to the visual spectra, reflectance in the near infrared domain (~ 700-900 nm) appears to be almost linearly related to a broad range of SPM concentrations. To reduce the number of parameters, the reflectance function (optical model) was approximated with a previously experimentally verified exponential equation (Schiebeet al., 1992: Remote sensing of suspended sediments: the Lake Chicot, Arkansas project, Int. J. Remote Sensing,13, 8, 1487-1509). The SPM term in Schiebe's equation was expressed as a linear function of top-of-atmosphere reflectance. This made it possible to calibrate the reflectance in the visual domain by reflectance values from the near-IR portion of the spectrum. The possibility to retrieve SPM concentrations from only remote sensing data without any auxiliary ground mea-surements is tested on a Landsat ETM + scene acquired over a reservoir with moderately turbid water with SPM concentrations between 15-70 g m-3. The retrieved concentrations (on average) differ from in-situ measurement by ~ 10.5 g m-3.

Decoherence-immune generation of highly entangled states for two atoms

This paper proposes a decoherence-immune scheme for generating highly entangled states for two atoms trapped in a cavity. The scheme is based on two resonant atom-cavity interactions. Conditional upon the detection of no photon, the two atoms may exchange an excitation via the first resonant interaction, which leads to entanglement. Due to the loss of the excitation, the two atoms are in a mixed entangled state. With the help of an auxiliary ground state not coupled to the cavity mode, the state related to the excitation loss is eliminated by the detection of a photon resulting from the second resonant interaction. Thus, the fidelity of entanglement is almost not affected by the decoherence.

Measurement Error Analysis of Ground Resistance Using the Fall-of-Potential Method According to the Locations of Auxiliary Probes

This paper presents numerical analysis of measurement errors of ground electrode using the fall-of-potential method. In order to analyze ground resistance error according to the positions of auxiliary probes, firstly, national and international standards were researched. Secondly, numerical ground resistance error of hemispheric electrode was analyzed according to the locations of auxiliary probes and the angle between probes. Then, error-reduced positions of auxiliary probes were shown according to the distance to auxiliary current probe versus ground electrode size. Finally, error compensation method was presented. The results presented in this paper provide useful information regarding ground resistance error of alternative positions of auxiliary probes in case that the auxiliary probes could not be located at the proper position in such cases as there are buildings, roadblock or underground metallic pipe at that position.

Study of Measurement Technique of Resultant Resistance in the Underground Distribution System

To realize the effective management of grounding resistances, it is necessary to establish a measuring technique of resultant resistance. Especially on underground system, it is too complex the connection of grounding system to understand the resultant resistance exactly by using of calculation, etc.Therefore, we propose a new measuring technique of resultant resistance. That is the way to apply the voltage on two different circuits with auxiliary grounding electrode, and to measure each current of the route on the circuits. Additionally, we produced a test measuring equipment, and performed the verification on electric circuits, practice lines and commercial lines.

보조접지그리드의 시설에 의한 대지표면전위경도의 저감

보조접지그리드의 시설에 의한 대지표면전위경도의 저감

A new method and instrument for touch and step voltage measurements

This paper describes a new method and instrument for measuring touch and step voltages near a grounding system, for example in and around a substation. The hardware, software, and testing procedures are an extension of the smart ground multimeter, developed under EPRI sponsorship. The instrument injects a transient electric current between the ground under testing and an auxiliary ground, and it measures ground potential differences (GPDs) at up to six locations. The GPD measurements are processed with software which rejects external noise using correlation methods. Subsequently, statistical estimation methods are used to extract the touch or step voltages from the thousands of measurement points normalized with the system short circuit capability. Knowledge of the short circuit capability of the substation allows the quick measurement of the touch and step voltages.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A PC based ground impedance measurement instrument

A PC-based instrument for ground impedance measurements is presented. The instrument injects a transient electric current between the ground under measurement and an auxiliary ground, and it measures ground potential differences (GPDs) around the ground under measurement. The GPD measurements are processed with software which rejects external noise by the use of correlation methods. Estimation methods are used to extract the ground potential rise and ground impedance. The final result is the ground impedance versus frequency in a user-selected frequency range. The instrument has been constructed and field tested by three electric utilities.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The Electrical Aspects of Cogeneration System Design

Cogeneration and the reasons that it is a viable industry today are discussed. Both bottoming and topping cycles may be employed for cogeneration; however, the topping cycle is the major focus of current cogeneration projects due to its applicability in large cogeneration power plants. The effect and reasons for the Public Utility Regulatory Policies Act removal of many of the disincentives of cogeneration are discussed. The relative efficiencies of conventional and combined-cycle cogeneration power plants are compared in a typical example of a large cogeneration power plant currently under construction. Many considerations face the electrical engineer in the design of a cogeneration power plant. Many applications will be found in industrial plants and will utilize industrial thinking within the plant; however, many decisions will be influenced by conventional electric utility thinking, due to the interface with the electric utility in the switchyard. Basic discussion of the considerations required of the electrical engineer, including electrical system arrangement, integration of the new generation into the plant electrical system, short-circuit matters, one-line diagrams, generator characteristics, excitation systems, step-up transformer ratings and characteristics, auxiliary transformers (station service), distribution systems, and system grounding, is given for preliminary guidance in design.

A Multipurpose Global Satellite Navigation System

A navigation system using information gathered from a cluster of four non-coplanar synchronous orbital satellites is proposed. The system consists of:1.At least one cluster of four non-coplanar satellites,2.Auxiliary ground stations for satellite tracking and data processing,3.User equipment.Since the cost of user equipment, in particular the computing cost, plays a very significant part in commercial feasibility of any satellite navigation technique, a special emphasis is placed upon the simplicity of computation algorithm and the feasibility of a small hard wired special purpose digital computer. The system operates on the range differences and range rate differences between the pair of satellites and the satellite ephemeris obtained by tracking. A tremendous amount of computation simplicity at the user end is achieved by preprocessing the ephemerous information and telemetering instead of the ephemeris data, this preprocessed data. The user computing equipment varies from a special purpose slide rule for a fixed terrestrial user to a simple digital computer for a fast moving aircraft. A sophisticated dispJay equipment can be used to display longitude, latitude, altitude, velocity, and heading. The analytical details for computation and error analysis are shown in the body of the paper. The major contribution of this paper is the development of a computational technique which results in an inexpensive, hard wired, modular type user computing equipment.

Vela satellite system detector electronics

The block diagrams of detector electronics used in the Vela Satellite Program are discussed in this paper. The auxiliary ground equipment used in conjunction with these instruments is mentioned along with details on the design of two circuits more commonly used in the Vela Satellite detectors.